Battery packs including a plurality of batteries accommodated in a case to allow an output of a predetermined voltage and capacitance are widely used as power supplies of various devices, vehicles, etc. The technique of forming modules of battery assemblies obtained by connecting general-purpose batteries in parallel and/or in series to output a predetermined voltage and capacitance, and of combining the resultant battery modules together to be applicable to various applications has begun to be adopted. This module forming technique can reduce the size and weight of the battery modules themselves by enhancing the performance of batteries accommodated in the battery modules. Thus, this module forming technique has various advantages: for example, workability in assembling a battery pack can be improved, and the flexibility in mounting battery modules in a limited space, such as a vehicle, can be increased.
On the other hand, as the performance of batteries accommodated in battery modules is enhanced, in addition to ensuring safety of individual batteries, it becomes more and more important to ensure safety of the battery modules constituted of multiple batteries. In particular, when heat generated due to, e.g., an internal short circuit in a battery produces gas, and the high-temperature gas is released to outside the battery by means of operation of a safety valve, neighboring batteries are subjected to the high-temperature gas. In this case, normal batteries affected by the high-temperature gas may be deteriorated in a chain reaction.
To solve the above discussed problems, Patent Document 1 describes a power supply device in which a case accommodating a plurality of batteries is partitioned by a partitioning wall into a battery chamber accommodating the batteries, and an exhaust chamber through which high-temperature gas released from the batteries is expelled, wherein the power supply device includes an exhaust mechanism which is configured such that openings of safety valves of the batteries are in communication with the exhaust chamber. With the exhaust mechanism thus configured, the high-temperature gas released through the safety valves of the batteries is caused to flow into the exhaust chamber without flowing into the battery chamber, and is expelled to outside the case through a vent of the case. This mechanism can prevent the high-temperature gas from filling the battery chamber and from coming into contact with the neighboring batteries, and thereby can reduce the influence on the normal batteries.